Generally speaking, circuit boards with more than 8 layers are called multi-layer circuit boards, which are very different from traditional PCB multilayer boards. For example, the processing and production are more difficult and the product stability is higher. Due to its wide range of applications, it has great potential for development. At present, most of the domestic manufacturers of multilayer circuit boards are Sino-foreign joint ventures, or even directly foreign companies. The multi-layer circuit board has relatively high requirements on the process level, and the initial investment is large. It not only requires advanced equipment, but also a test for the technical level of the staff. In addition, the user authentication procedures are cumbersome, so that many circuit board manufacturers do not have the ability to produce multi-layer circuit boards, so there are still many multi-layer circuit boards. considerable market prospects.

　　The following are some points that I think should be paid attention to in the production process of PCB circuit board:

　　1. Alignment

　　The more layers of the circuit board, the higher the requirements for the alignment between layers. Generally speaking, the alignment tolerance between layers is controlled within ±75μm. Due to the influence of factors such as size and temperature, it is very difficult to control the alignment degree between layers of the PCB circuit board.

　　2. Inner line

　　The materials for making PCB circuit boards are also very different from other boards. For example, the surface copper skin of PCB multilayer boards is thicker. This increases the difficulty of laying out the inner layers. If the inner core board is relatively thin, it is prone to abnormal exposure, which may be because of wrinkles. Generally speaking, the unit size of the PCB circuit board is relatively large, and the production cost is high. Once a problem occurs, it will be a huge loss for the enterprise. It is very likely that there will be a situation of making ends meet.

　　PCB multilayer board

　　3. Press fit

　　It is called a multi-layer circuit board, and there must be a pressing process. In this process, if you are not careful, there will be phenomena such as layering and skateboarding. So we have to consider the properties of materials when designing. The more layers there are, the more difficult it is to control the amount of expansion and shrinkage and the amount of size factor compensation, and problems will follow. If the insulation is too thin, a test failure may occur. Therefore, more attention should be paid to the pressing process, and there will be more problems at this stage.

　　4. Drilling

　　Since special materials are used to make PCB multilayer circuit boards, the difficulty of drilling holes has also increased a lot. Drilling technology will also be a test. Due to the increased thickness, the drilling tool is easy to break, and there may be a series of problems such as oblique drilling. Everyone should pay more attention!

　　The above are some of the difficulties in the production process that I think are some of the difficulties. If there are any omissions, I hope you will criticize and correct them! You are welcome to leave a message in the comment area.

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